“Brushless” automated vehicle washing systems are commonly utilized to quickly and efficiently clean vehicles without requiring any hand scrubbing or contact between cleaning members and the exterior of a vehicle. Brushless vehicle washing systems utilize jets of pressurized cleaning fluid sprayed from a plurality of nozzles to wash away dirt and grime from the exterior surfaces of a vehicle. In one common type of washing system, the nozzles are commonly arranged in a gantry. The gantry either 1) passes over and around the vehicle or 2) is stationary and the vehicle passes through it. In either instance, the nozzles direct jets of cleaning fluid over most if not the entire exterior surface of the vehicle.
The cleaning efficiency and effectiveness of a vehicle washing system is largely dependent upon two factors: the force at which the pressurized cleaning fluid impinges on the vehicle surface; and the effective area on the vehicle's surface impacted by the pressurized cleaning fluid. In order to effectively clean the entire surface of a vehicle, the cleaning fluid jet must impact the adjacent surface with a requisite amount of force in order to dislodge any dirt or foreign matter resident on the adjacent surface. The amount of force per unit area imparted on the adjacent surface is dependent on several factors including the speed and angle at which the jet of cleaning fluid impacts the adjacent surface. As the distance between the nozzle and the adjacent surface increases, the speed of the cleaning fluid decreases; also the jet begins to fan increasing the impact area on the adjacent surface, thereby spreading the impact force over a greater area, and reducing cleaning effectiveness. Accordingly, those parts of a vehicle that are furthest from the nozzles may not be adequately cleaned.
Typically, gantry-type cleaning systems have the most difficulty cleaning the front and rear of a vehicle, since the nozzles located at the sides and top of the gantry normally direct jets of cleaning fluid parallel or at a very shallow angle to the vehicle's front and rear surfaces. Gantry-type washing systems have been developed wherein overhead nozzles are mounted on moveable platforms that (1) pivot to increase the angle of incidence between the fluid jet and the front and rear surfaces of the vehicle, (2) move vertically to decrease the distance between the nozzles and front and rear surfaces, or (3) both pivot and move vertically. The last type of moveable platform is preferred, wherein the platform maybe lowered to get close to front or rear surfaces and pivoted so that the fluid jets impact the surface at a desired angle.
Despite what type of vehicle washing system is utilized, vehicle owners often desire the option of applying additional specialty solutions to their vehicle, such as spot free rinse solutions and clear solutions. Both of these solutions are relatively expensive when compared to the other liquids used during the wash cycle such as water. Accordingly, it is desirable to minimize waste of the specialty solutions, while maximizing coverage of the vehicle's surface. Current art gantry-systems apply these solutions in a number of ways. Using one method, specialty solutions may be applied through the same high-pressure nozzles that are utilized to apply the cleaning and rinsing solutions. This is undesirable for at least two reasons: one, the specialty solution left in the supply lines must be purged prior to the beginning of the next vehicle wash; and two, the use of a high pressure delivery device might deliver a greater than necessary volume of specialty solution to the vehicle as the gantry traverses the vehicle's length. The result is an inefficient use of the expensive specialty solutions. It is noted that high-pressure delivery of specialty fluid is rarely necessary since specialty solutions are chemical cleaners, not dynamic cleaners; accordingly, the primary goal when applying a specialty solution is simply to obtain complete vehicle coverage.
Another method utilized to apply specialty solutions has been to spray the specialty fluid, often in the form of a foam, onto the sides of the vehicle from discharge openings spaced along vertical dispensing tubes attached to the gantry's side legs. The problem of inefficiency is minimized, since there is no need to purge the dedicated specialty fluid delivery system after each vehicle wash. Unfortunately, these vertically mounted delivery systems have difficulty in delivering solution in a manner that completely covers the top surfaces of a vehicle as there is often little impetus for the applied specialty solution to flow along the horizontal top surfaces of the vehicle, especially when the solution is in the form of a foam.